Battery SOC Correction via Hysteresis Voltage Interval Segmentation
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Solution Overview
Problem
Existing SOC estimation methods for batteries with hysteresis characteristics suffer from inaccuracies due to changes in open-circuit voltage (OCV) curves caused by historical operating conditions, leading to errors in state of charge (SOC) correction.
Innovation Solution
A method that determines whether the current OCV measurement is within a hysteresis voltage interval, and if so, calculates both charging and discharging SOC values to establish a SOC confidence interval for correcting the current SOC, using a Preisach model to account for historical operating conditions and improve accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the open-circuit voltage (OCV) method is used to obtain SOC in a static state, then the SOC estimation is simple to implement, but the accuracy deteriorates due to hysteresis characteristics causing OCV curve changes
Solution Approach 1:
The patent divides the single OCV-SOC correspondence into separate charging and discharging OCV curves. By segmenting the hysteresis loop into distinct charging and discharging paths, the system can select the appropriate curve based on the current battery state, thereby resolving the accuracy issue caused by hysteresis while maintaining the simplicity of the OCV method.
Solution Approach 2:
The patent introduces dynamic selection of OCV curves based on the battery's charging or discharging state. Instead of using a static OCV-SOC relationship, the system dynamically switches between charging and discharging curves according to the current operating condition, which accounts for hysteresis effects and improves accuracy.
2Measurement precision
If the hysteresis voltage interval is considered to improve SOC accuracy, then the measurement precision is improved, but the device complexity increases due to additional determination steps
Solution Approach 1:
The patent segments the voltage range into hysteresis and non-hysteresis intervals, applying different correction strategies to each. This segmentation allows the system to handle complex hysteresis effects only where necessary while using simpler methods elsewhere, balancing accuracy improvement with system complexity.
Solution Approach 2:
The patent applies different levels of correction complexity to different voltage regions. In the hysteresis voltage interval, the system uses the more complex dual-curve method, while in non-hysteresis regions, it uses the simpler single-curve approach. This local differentiation optimizes accuracy where needed while minimizing overall system complexity.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach enhances the accuracy of SOC estimation by considering hysteresis characteristics, providing a more precise SOC correction by differentiating between charging and discharging states and using confidence intervals to adjust the SOC value accordingly.
Implementation Method 1
for a battery having a hysteresis characteristic, an OCV curve characterizing the correspondence between the OCV and the SOC may be affected by historical operating conditions
Data Source
AI summary
The present disclosure provides a method, a device, a system, and a storage medium for SOC correction for a battery. The method includes determining a current OCV measurement value of the battery, and determining whether the current OCV measurement value is within a hysteresis voltage interval; determining, when the current OCV measurement value is within the hysteresis voltage interval, a charging SOC value corresponding to the current OCV measurement value in the charging state and a discharging SOC value corresponding to the current OCV measurement value in the discharging state; and determining, based on a SOC confidence interval determined from the charging SOC value and the discharging SOC value, a SOC correction target value to correct a current SOC value of the battery. The embodiments of the present disclosure may implement SOC correction for the battery having a hysteresis characteristic to improve estimation accuracy of the battery SOC.